Dynamic signal tracking in a simple V1 spiking model

TL;DR

This study models a simplified V1 neural circuit to investigate how it tracks moving visual signals, revealing transient perception overshoots and reduced accuracy at orientation reversals, aligning with psychophysical data.

Contribution

It introduces a ring model of spiking neurons that explains dynamic signal tracking limitations and perceptual phenomena in the primary visual cortex.

Findings

Transient overshoots in perception after signal switches

Lower accuracy at orientation reversals during continuous movement

Model's firing rates match experimental data

Abstract

This work is part of an effort to understand the neural basis for our visual system's ability, or failure, to accurately track moving visual signals. We consider here a ring model of spiking neurons, intended as a simplified computational model of a single hypercolumn of the primary visual cortex. Signals that consist of edges with time-varying orientations localized in space are considered. Our model is calibrated to produce spontaneous and driven firing rates roughly consistent with experiments, and our two main findings, for which we offer dynamical explanation on the level of neuronal interactions, are the following: (1) We have documented consistent transient overshoots in signal perception following signal switches due to emergent interactions of the E- and I-populations, and (2) for continuously moving signals, we have found that accuracy is considerably lower at reversals of orientation than when continuing in the same direction (as when the signal is a rotating bar). To measure performance, we use two metrics, called fidelity and reliability, to compare signals reconstructed by the system to the ones presented, and to assess trial-to-trial variability. We propose that the same population mechanisms responsible for orientation selectivity also impose constraints on dynamic signal tracking that manifest in perception failures consistent with psychophysical observations.